1. Field of the Invention
The present invention relates to a data storage apparatus, and more particularly, to a data storage apparatus using current switching in a metal oxide layer.
2. Description of the Related Art
A method of recording data to store and reproduce the data may be typically categorized into a magnetic recording method, an optical recording method, and an electrical recording method. Nowadays, the magnetic recording method is being widely used for a high-capacity storage apparatus, and the optical recording method is being efficiently utilized for portable use. In recent years, a data storage apparatus using electricity, such as a flash memory device, has spread at high speed along with technical development and retrenchment of production cost.
However, the above-described data recording methods have some shortcomings. For example, in the case of magnetic recording, even if a magnetic sensor, which is used to record and reproduce data, is of highest sensitivity, the maximum storage density is restricted due to superparamagnetic limit. In the case of optical recording, since there is diffraction limit according to the wavelength of light used for recording and reproduction of data and the numerical aperture of a lens, it is difficult to improve storage density.
By comparison, in the case of electrical recording, there is no substantial limit to the size of mediums to which current is supplied to store data. Therefore, it is highly likely that storage density will greatly increase. In general, it is considered that the electrical recording method may be applied to a flash memory device, which stores data by injecting charges into a SiNxOy layer, or a ferroelectric random access memory (FRAM), which makes use of dielectric polarization of a high-k dielectric material.
However, the flash memory device includes a charge injection region for storing electrical data, which is located in a trap state disposed at an interface of the SiNxOy layer. In this case, it is difficult to uniformly control the density of the trap state. Also, the phenomena of aging result from repetition of writing and erasing. The FRAM also has similar problems. As the thickness of the dielectric material decrease, the magnitude of the dielectric polarization decreases, thus the FRAM loses its ferroelectric characteristic. Furthermore, thermal damage is caused by a fabricating process and repetition of writing and erasing leads the FRAM to grow older.
Therefore, it is necessary to develop a new data storage apparatus that is structurally simple and involves simple fabricating processes. Also, the data storage apparatus needs a nanoscale control precision to elevate storage density. Further, the data storage apparatus should process data at an ultrahigh integration density so that it can greatly improve in production cost and storage density.